A headlamp, also sometimes known as an optical unit, is generally formed by a casing that encloses one or more light sources and by means for fixing to structural elements of the vehicle.
Currently, motor vehicle manufacturers design the connections between the headlamp and the structural elements of the vehicle such that the dynamics of the headlamp meet a number of requirements in the event of a frontal impact.
These criteria are essentially the criteria associated with pedestrian impacts, with damage to the surrounding components in the event of a frontal impact or to the design of the vehicle.
Specifically, the dynamics of a headlamp must be compatible with a pedestrian impact in order to reduce the risk of injury, for example in the region of the hip, femur or tibia.
In particular, regulations impose constraints with regard to tibia impacts. In order to respect these regulations, some manufacturers have added a relatively soft absorber in front of the impact cross member of the vehicle, having the effect of increasing the crumple distance of the vehicle under an equal amount of frontal impact energy.
Furthermore, for hip/tibia/femur pedestrian impacts, it is preferable for the dynamics to allow the headlamp to move backward so as to reduce the risks of injury. This has led to the removal of some connections, one of the functions of which was to prevent the headlamp from moving backward in the event of a frontal impact.
Furthermore, headlamps are becoming increasingly voluminous on account of vehicle design and the integration of new functions. Developments in vehicle design mean that the protection of the headlamp with respect to obstacles is becoming increasingly weak.
All of these factors increase the exposure of headlamps to frontal impacts and the amplitude of their movement. The direct effect of this is to increase the risks of damage to surrounding components, in particular the front fender, in the event of impacts.
Solutions exist which limit the damage to the front fender by the headlamp in the event of a frontal impact.
One solution, described in document FR 2 850 719 consists of a system of pivoting pins that allow the fender to be detached from its support under the action of the headlamp without being damaged. Such a solution, in order to operate optimally, requires the fender to be fixed to the structure of the vehicle along a vertical axis, and this may be a constraint in the assembly process of the vehicle.
Another solution, described in document FR 2 895 954 A1 comprises the production of a connecting member that is disposed under the casing of the headlamp and pivots about a vertical axis disposed in a housing at the head of the front chassis frame side rail of the vehicle. In the event of a frontal impact, the connecting member pivots and causes the casing to pivot toward the outside of the vehicle without damaging the fender. This solution requires the presence of a clearance between the fender and the casing of the headlamp, concealed by a trim molding, and the production of a pivoting connecting member.